Human Anaplasmosis Statistics

In 2014, 448 confirmed or probable cases of anaplasmosis (8.3 cases per 100,000 population) were reported, down from the 627 cases reported in 2013. Despite these occasional decreases in reported cases, the overall trend is an increase in yearly case totals over time.  Two hundred ninety-two (65%) cases reported in 2014 were male. The median age of cases was 59 years (range, 3 to 87 years), 20 years older than the median age of Lyme disease cases.  As is typical, most cases had illness onsets during the summer months, with 58% of cases reporting illness onsets in June and July.  In 2014, 124 (28%) anaplasmosis cases were hospitalized at some point for their infection, with a median duration of 4 days (range, 2 to 17 days).

The number of anaplasmosis cases has been increasing since the first cases of HA were reported in Minnesota in the mid-1990s. A variety of factors, including increasing physician awareness, increasing infection rates in ticks, and expanding tick distribution, may have led to this trend.

On this page:
Charts and graphs
Annual summaries
National Statistics

Charts and Graphs


Most HA cases report likely exposure to blacklegged ticks in the same east-central and north-central Minnesota counties where the risk of Lyme disease is greatest.

Annual Summary Statistics

National Statistics

Updated Thursday, August 06, 2015 at 11:54AM